2. Sources and allusions:
A. The leak marks come from the dialogue between Yan Zhenqing and Huai Su. Like the case-solving of Zen Buddhism, it is a pen method witnessed and realized by literati. The lines drawn by this pen method are considered by the ancients to be the purest, purest, most aesthetic and most tasteful lines.
B. In the Tang Dynasty, Lu Yu's "shihuaisu and Yan Zhenqing on cursive script" contained: Yan Zhenqing and Huai Su talked about calligraphy, and Huai Su said: "I think Xia Yun has many strange peaks, and its pleasure is like a bird out of the forest, a snake into the grass, a cliff and a natural road." Yan Zhenqing said, "What's the leak?" Huai Su got up and shook hands and said, "You got it!" In addition, in the Southern Song Dynasty, Jiang Kui's "Continued Book Spectrum" said: "If there are leaks in the family, I want it to be endless."
3. Style and Masterpieces: Masterpieces Magu Xiantan, Yanjia Temple Monument and Yanjia Temple Monument; Huang Tingjian's Hua Yan Jing, Mi Fei's Poems of Hong Xian, etc.